This invention relates generally to gas turbine engines, and specifically to turbofan engines for aircraft. In particular, the invention concerns a repair or maintenance apparatus for the fan disk and rotor assembly of a turbofan engine.
Gas turbine engines (or combustion turbines) are built around a power core made up of a compressor, combustor and turbine, arranged in flow series with an upstream inlet and downstream exhaust. The compressor compresses air from the inlet, which is mixed which fuel in the combustor and ignited to generate hot combustion gas. The turbine extracts energy from the expanding combustion gas, and drives the compressor via a common shaft. Energy is delivered in the form of rotational energy in the shaft or reactive thrust from the exhaust, or both.
Gas turbine engines provide reliable, efficient sources of energy for a wide range of applications, including industrial power generation, aviation and commercial heating and cooling. Larger-scale gas turbine engines include a number of different compressor and turbine sections, which are arranged into coaxially nested spools. The spools operate at different pressures and temperatures, and rotate at different speeds. Individual compressor and turbine sections are subdivided into a number of stages, which are formed of alternating rows of rotor blade and stator vane airfoils. The airfoils are shaped to turn, accelerate and compress the gas flow, and to generate lift for conversion to rotational energy in the turbine.
Aviation applications include turbojet, turbofan, turboprop and turboshaft engine designs. Turbojets are an older configuration, in which thrust is generated primarily from the exhaust. Modern turbofan and turboprop engines typically utilize a two-or three-spool arrangements, in which the low-pressure spool is coupled to a propulsion fan or propeller. Turboshaft engines are used on rotary-wing aircraft, including helicopters.
Turbofans are commonly divided into high and low bypass engines. High-bypass turbofans generate most of their thrust via the fan, which drives airflow through a bypass duct oriented around the engine core. Low-bypass turbofans generate more power from the exhaust flow, delivering greater specific thrust but at some cost in noise and fuel efficiency, and are used on supersonic fighters and other high-performance aircraft.
In general, commercial aircraft trend toward higher bypass turbofan designs, in order to increase fuel efficiency at cruise. The corresponding fan disk and rotor assemblies are relatively large, requiring specialized equipment for maintenance and repair.